Direct chip interconnect with adhesive-connector films

The authors discuss the results of feasibility studies of direct chip interconnect (DCI) using anisotropic conductive polymer material on both flexible and rigid substrates. The concept is to simultaneously attach and electrically interconnect IC chips to circuit traces. When conductors are joined under heat and pressure to form a bond, metallic spheres within the adhesive layer make contact with both conductor surfaces but not each other; hence the anisotropic conductivity. Electrically anisotropic conductive adhesives offer numerous other advantages in the assembly of electronic circuits, including low temperature assembly, fluxless bonding which eliminates the need for cleaning, and low cost. In addition, the anisotropy inherent in these materials makes them excellent candidates for very fine pitch components